Optoelectronic components on an organic basis, for example an organic light emitting diode (OLED), are being increasingly widely used in general lighting, for example as a surface light source. A conventional organic optoelectronic component, for example an OLED, may include an anode and a cathode with an organic functional layer system therebetween. The organic functional layer system includes one or a plurality of emitter layer(s) in which electromagnetic radiation is generated, one or a plurality of charge generating layer structure(s) each composed of two or more charge generating layers (CGL) for charge generation, and one or a plurality of electron blocking layer(s), also designated as hole transport layer(s) (HTL), and one or a plurality of hole blocking layer(s), also designated as electron transport layer(s) (ETL), in order to direct the current flow.
The areal luminous impression of an OLED is intended to be maintained as far as possible in many applications. In various applications, the emission characteristic of an OLED is intended to be able to be altered during operation, for example from a directional light beam to the beam profile of a Lambertian emitter.
In one conventional method, the emission characteristic of an optoelectronic component is altered by macroscopic optical components, for example by reflectors or lens systems. Such a macroscopic modification is unsuitable in surface light sources since the surface impression is lost.
In one conventional method, microlenses are used in an attempt to alter the emission characteristic of an organic light emitting diode. However, the emission characteristic of an OLED cannot thereby be altered in a variable manner.
In a further conventional method, a scattering structure is formed from microlenses embedded in a matrix, wherein the microlenses and the matrix have a different temperature-dependent refractive index. As a result, the emission characteristic can be altered depending on the temperature of the scattering structure. A temperature-controlled change of the emission characteristic is sluggish, however. Furthermore, such driving can be locally imprecise and produce an inhomogeneous appearance.
It is furthermore known to use liquid crystals to change the polarization of an electromagnetic radiation in liquid crystal screens and displays (liquid crystal display—LCD). Most liquid crystals are optically birefringent, which can be identified under a polarization microscope by characteristic textures. Under the influence of an external electric field, the orientation of some liquid crystals can be influenced in a targeted manner and, for example, the polarization of light can thus be altered.